The present invention relates to the marking of metal for tracking and identification purposes, and more particularly to imprinted metal tags that can be nail attached to metal workpieces.
Primary metal mills require that their products be accurately identified. Molten metal batches have unique “heat” (batch) chemistries that affect the mechanical properties of the ultimate (further formed) end products. Tracking the many individual pieces produced from a heat is a difficult, time-consuming process with many opportunities for error in the stressful (hot, noisy, dimly lit, and physically dangerous) mill environment.
Metals first exit the molten heat as very hot (e.g., 1,800° F. or 982° C.) slabs, blooms, or billets. Ideally, these slabs, blooms, and billets should be identified with bar coded information immediately after they solidify and while they are still on the run out tables (before they can be mixed up). Automatic identification (e.g., bar codes) is preferred because it helps eliminate the errors inherent in manual marking and reading (estimated by some to be as high as 1 in 300 attempts).
High temperature tags (some with bar codes) have been used for some time. For example, such tags may be manually affixed to the slab or billet using a powder charged or pneumatically driven nail gun. Efforts to automate this prior art tag attachment have generally not been successful, because, the nailing mechanism is difficult to automate, as the environment is not conducive to bowl feeders. Nail “sticks” are limited to, say, 50 nails and stick feeds are unproven. There are also ergonometric and safety issues with the standard gun offerings.
The present invention addresses the need for attachment of tags to hot metal, including hot stainless steel, with an automatic nail gun and more generally to a novel nail module.